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Sakasegawa, Hideo
ENEKAN, 20, p.20 - 23, 2022/07
no abstracts in English
Sakai, Akihiro
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 29(1), p.48 - 54, 2022/06
no abstracts in English
Ogawa, Rina; Abe, Daichi*; Sugaya, Toshikatsu; Sakuma, Kota; Saito, Tatsuo; Sakai, Akihiro
JAEA-Technology 2022-008, 46 Pages, 2022/05
JAEA-Technology-2022-008.pdf:3.09MB
Japan Atomic Energy Agency (JAEA) has planned to dispose of the Uranium-bearing waste, whose radioactivity concentration is low, in trench disposal facility. In Japan, uranium is a material to impact on human health, therefore Environmental quality standards for water pollution for uranium has been established, and the standard value is 0.002mg/L. Safety of trench disposal facilities will be assessed that radionuclides contained in the radioactive waste are transferred to the biosphere by seepage water and groundwater. Therefore, JAEA considers that not only dose evaluation but also environmental pollution evaluation is needed as a safety assessment. In this report, we examined whether the concentration of uranium leaching from the trench facility in the aquifer can meet the Environmental quality standards. In addition, parameter study under various conditions of disposal facility were done. Based on the results, conditions and issues of future basic design of trench disposal facility were discussed. The uranium concentration in the aquifer was calculated by the one-dimensional dose evaluation code "GSA-GCL2" for the disposal of LLW. As the result, the uranium concentration in the aquifer significantly changed depending on the conditions of design of disposal facility and so on. However, if the shape and arrangement of the trench facility to groundwater flow direction, the distribution coefficient of uranium of the waste layer, the specification of the impermeable layer and their combination are appropriately designed we consider that the uranium concentration of aquifer can made to adapt the environmental quality standard.
Ozu, Akira; Komeda, Masao; Kureta, Masatoshi; Nakatsuka, Yoshiaki; Nakashima, Shinichi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 59(12), p.700 - 704, 2017/12
no abstracts in English
Ozu, Akira; Komeda, Masao; Kureta, Masatoshi; Zaima, Naoki; Nakatsuka, Yoshiaki; Nakashima, Shinichi
Nihon Genshiryoku Gakkai Wabun Rombunshi, 15(2), p.115 - 127, 2016/06
A non-destructive assay system using the fast neutron direct interrogation method has been developed to put its method into practical use for the determination of uranium (
U) mass contained in actual uranium-contaminated waste drums. The method is capable of measuring the fissile mass in a drum by counting the number of fission neutrons resulting from nuclear fission reactions between the fissile materials contained in a drum and thermal neutrons generated by 14 MeV fast neutrons irradiated from outside the drum. The performance test employing simulated metal waste drums demonstrated that a natural uranium mass of as low as 10 g could be detected within an error of 
20% regardless of the distribution of uranium samples in the drum. A demonstration test employing actual waste drums could determine the uranium mass by using a newly developed correction method for deriving the fissile mass in a drum. It has been proved by the experimental validation tests that the assay system equipped with the correction method is very useful for the accountancy of the waste drums.
Sakurai, Takeshi; Kosako, Kazuaki*; Mori, Takamasa
Monte Karuro Keisanho Kodoka No Genjo; Dai-3-Kai Monte Karuro Shimyureshon Kenkyukai Hobunshu, p.168 - 176, 2004/12
no abstracts in English
Kanno, Mitsuhiro*; Takeda, Seiji; Minase, Naofumi; Kato, Hideo; Kimura, Hideo
JAERI-Conf 2004-011, p.131 - 132, 2004/07
no abstracts in English
Meguro, Yoshihiro; Tomioka, Osamu; Imai, Tomoki*; Fujimoto, Shigeyuki*; Nakashima, Mikio; Yoshida, Zenko; Honda, Tadashi*; Koya, Fumio*; Kitamura, Nobu*; Wada, Ryutaro*; et al.
Proceedings of International Waste Management Symposium 2004 (WM '04) (CD-ROM), 8 Pages, 2004/03
Supercritical CO
fluid leaching (SFL) method using supercritical CO fluid containing a complex of HNO
- tri-n-butyl phosphate (TBP) was applied to removal of uranium from radioactive solid wastes. Sea sands, incineration ashes and porous alumina bricks were employed as matrixes of simulated solid wastes. Real radioactive incineration ash wastes and firebrick wastes were also subjected to the SFL treatment. It was found that uranium could be efficiently removed from both of the simulated wastes and real wastes by the SFL method. The removal efficiency of uranium from the real waste was lower than that from the corresponding artificial waste. About 1 g and 35 mg of uranium were recovered from 10 g of the real ash waste and 37 g of the real firebrick waste, respectively.
Takeda, Seiji; Kimura, Hideo
JAERI-Conf 2003-018, p.111 - 112, 2003/10
no abstracts in English
Takeda, Seiji; Kanno, Mitsuhiro; Minase, Naofumi; Kimura, Hideo
Journal of Nuclear Science and Technology, 39(8), p.929 - 937, 2002/08
no abstracts in English
Kimura, Hideo
Genshiryoku Bakkuendo Kenkyu, 8(2), p.103 - 114, 2002/03
no abstracts in English
fluid leaching (SFL) of uranium from solid wastes using HNO-TBP complex as a reactantTomioka, Osamu*; Meguro, Yoshihiro; Iso, Shuichi; Yoshida, Zenko; Enokida, Yoichi*; Yamamoto, Ichiro*
Proceedings of International Solvent Extraction Conference 2002 (CD-ROM), p.1143 - 1147, 2002/00
no abstracts in English
Sakamoto, Yoshiaki; Ishii, Tomoaki*; Inagawa, Satoshi*; Gunji, Yasuyoshi*; Takebe, Shinichi; Ogawa, Hiromichi; Sasaki, Tomozo*
Genshiryoku Bakkuendo Kenkyu, 8(1), p.65 - 76, 2001/09
In order to study adsorption behavior of U series radionuclides(Pb, Ra, Th, Ac, Pa and U) in aerated zone environment (loam-rein water system) and aquifer environment(sand-groundwater system) for safety assessment of U bearing waste), pH dependence of distribution coefficients of each element have been obtained. The pH dependence of distribution coefficients of U, Ac, Th, Ra and Pb was analyzed by model calculation of adsorption behavior based on chemical forms of each elements and soil surface characteristics, which are a cation exchange capacity and surface charge. From model calculation of adsorption behavior, the distribution coefficients' values and adsorption behavior of Pb, Ra, Th, Ac and U could be showed by a combination of cation exchange and surface-complexation adsorption model.
Ishii, Tomoaki*; Inagawa, Satoshi*; Gunji, Yasuyoshi*; Sakamoto, Yoshiaki; Takebe, Shinichi; Ogawa, Hiromichi; Sasaki, Tomozo*
Genshiryoku Bakkuendo Kenkyu, 8(1), p.55 - 64, 2001/09
Distribution coefficients of Uranium series nuclide(Pb,Ra,Ac,Th,Pa and U) were obtained under aerated zone environment and aquifer environment, for the safety evaluation of shallow underground disposal of uranium bearing waste. The distribution coefficients of them on 4 kinds of soil such as the loam in the rain water as for aerated zone environment and on 3 kinds of soil and rock such as the sand in groundwater as for aquifer environment have been measured by batch method. The distribution coefficients in aerated zone environment were one or two orders in magnitude higher than that in aquifer environment, except Ac. And, there was approximately the linear correlation on the relationship between cation exchange capacity and specific surface area, which are representative physical property of the soil, and distribution coefficient of lead, radium and protactinium.
Kimura, Hideo
KURRI-KR-56, p.95 - 108, 2001/03
no abstracts in English
Sakamoto, Yoshiaki; Takebe, Shinichi; Ogawa, Hiromichi; Muraoka, Susumu; Ishii, Tomoaki*; Inagawa, Satoshi*; Gunji, Yasuyoshi*
Materials Research Society Symposium Proceedings, Vol.663, p.1207 - 1214, 2001/00
no abstracts in English
Mine, Tatsuya*; Mihara, Morihiro; ; *; *
JNC TN8430 2000-003, 33 Pages, 2000/04
On the geological disposal system of the radioactive wastes, the activities of the microorganisms that could degrade the asphalt might be significant for the assessment of the system performance. As the main effects of the biodegradation of the asphalt, the fluctuation of leaching behavior of the nuclides included in asphalt waste has been indicated. In this study, the asphalt biodegradation test was carried out. The microorganism of which asphalt degradation ability was comparatively higher under aerobic condition and anaerobic condition was used. The asphalt biodegradation rate was calculated and it was evaluated whether the asphalt biodegradation in this system could occur. The results show that the asphalt biodegradation rate under anaerobic and high alkali condition will be 300 times lower than under aerobic and neutral pH.
Miyo, Hiroaki; Yoshida, Michihiro; *; Asami, Makoto*; Iso, Takahito*; *; *
PNC TN8440 96-010, 171 Pages, 1996/03
None
Zaima, Naoki; Nakatsuka, Yoshiaki; Nakashima, Shinichi; Ozu, Akira; Komeda, Masao; Kureta, Masatoshi
no journal, ,
JAEA developed NDA systems which applied to the actual scrapped nuclear materials and uranium bearing waste drums heavily generated from URCP and NEP in Ningyo-site. In order to improve the methodology of determination uranium mass the active assay neutron NDA measurement system (JAEA Waste Assay System-Ningyo=JAWAS-N) used by the Fast Neutron Direct Interrogation (FNDI) method have been configurated. The validation tests have been achieved successfully, also the trials for measuring the actual nuclear materials or waste drums just started and accumulated over 550 data with quick and high accuracy measuring. The die-away time, which means neutron decay time in phenomenon, may be used for analyzing uranium mass, at the same time, the neutron behavior simulations over time spectrum have been carried out and verified our measurement system.
Saito, Tatsuo
no journal, ,
Regarding low-level radioactive waste bearing uranium and NORM, we enumerated the historical developing for safety regulation concerning burial disposal and clearance, by the outline of the public reports for safety case about (1) radon and progeny nuclides, (2) natural nuclides and natural viability, (3) regulatory exemption, regulatory exclusion, clearance. The result of confirmation is as follows. (1) The guidelines for protection from NORM are consistent in our society and the country, and guidelines for intervention in existing radiation situation are applied. (2) In planned exposure, except for uranium clearance, discussion has been postponed on the basic concept of safety assessment concerning final disposal of waste due to handling of natural persistence. (3) With regard to radon, there were guidelines for describing treat with its natural universality partially considered and excluding international clearance standard concentrations below the Fukushima accident from the evaluation subjects, but the others are undecided. (4) In the deliberations on the intermediate depth in the disposal at the regulatory committee, uranium waste is excluded, and the waste in the reactor that can suppress latent exposure to the extent of pit disposal is targeted. (5) Introduction of intervention level is being considered for public exposure caused by human invasion after the management period, considering ultra long-term evaluation.
